1. Field of Invention
The present invention relates to plow systems which are designed to be easily attachable to light vehicles and the like.
2. Setting For the Invention
The major problems with most plow systems now available for use with light vehicles and light trucks are: (1) that they are easily damaged by obstacles (e.g., curbs, manhole covers, and drain grates) encountered during plowing; (2) that they are difficult to attach and then disconnect; (3) that the geometrical structure of their mounting brackets is such that it unnecessarily reduces the hill-approach angle of the vehicle; (4) that the blade yaw angles are unnecessarily limited; (5) that the ability of the blade to track (or roll with) the plowing surface's pitch is also unnecessarily limited; and (6) that the blades tend to damage roadways.
The above problems, when recognized, have been addressed in various ways, yet the basic geometries of preexisting systems conceived, exhibit that they have been designer selected with nonminimal compromise. Accordingly, the principle object of the present invention is to satisfy optimal design objectives with minimum compromise so that the major problems of preexisting plow systems can be overcome.
In conventional plow system designs, in order to enable the blade component thereof to remove all snow and ice accumulated from the plowing surface, and concurrently be capable of passing over rigid protruding objects from the plowing surface (such as manhole covers, pavement irregularities, curbs, etc.), conventional blades have been designed slightly curved, and they intersect the ground with a rake angle of about 70 degrees.
In the event that a rigid object is struck by the plow blade, one of two conventional types of blade protection have been hitherto designed and implemented into realization. The first protective blade mechanism allows the blade to tip forward and for the blade to slide over the encountered object. However, in this case, every time the blade tips the operator must replow a small section of the surface which the blade was not acting upon during the object disturbance. The second type of blade protection conventionally provided holds the upper part of the blade rigid while the lower four-or-so inches of the plow blade is hinged and is loaded by a compression-type spring from behind the blade. Thus, when the blade strikes a rigid object, the bottom edge of the blade momentarily folds under the blade structure assembly and allows the blade to glide over the encountered object. A major object of the present invention is to provide a blade geometry that overcomes the problems of damage done to the blade, to attaching assembly, to the road, and to the vehicle, due to road obstructions and to do so with a much simpler design.
In conventional plow system designs, the plow's A-frame assembly and blade are lowered into operating position and the blade angling (yawing) subsystem establishes the angular displacement of the blade using a hydraulic system. This choice not only contributes to a major part of the plow's manufacturing cost, but it limits the yaw angle of the blade to about thirty angular degrees measured about the longitudinal axis of the plow vehicle, as is later described. This performance limitation, set chiefly by --(1) design tradeoffs in the blade angling system's mechanical advantage against snow forces and (2) geometric/configurational constraints inherent in the placement of this subsystem's hydraulic cylinders on the plow's A-frame--poses a serious problem in achieving high plow performance. This limitation imposed upon the angular displacement of the blade is usually not enough to keep the angle of the plow's velocity vector constant with respect to the motion of the snow during sharp vehicle turns. Also, roll capability of the blade is due only to the elasticity of the plow's A-frame about the longitudinal reference axis of the vehicle's forward motion. Thus, when plowing on uneven roads or driveways having very large slopes (technically called roll), the bottom edge of the blade may not always track the contours of the surface being plowed. In order to overcome such problems, an electric winch/cable blade angling (yawing) subsystem and a blade connecting mechanism having three degrees of freedom have been incorporated into the present design, wherein, the design objectives (1) that the blade be capable of yawing forty-five degrees by remote control, and (2) that the blade be capable of rolling nine degrees, have been satisfied.
In a conventional plow system design, the plow system is attached to the vehicle beneath the front bumper. A chief shortcoming of this feature is that the connecting mechanism employed is unnecessarily bulky and can restrict ground clearance of the plow system as well as unnecessarily reduce the angle of the steepest hill that the vehicle is capable of approaching from a flat plane. In addition to ground clearance and vehicle approach angle problems, the conventional designs of plow system mounting brackets have posed other unnecessary problems; such as restricting access to the underside engine area for repairs. Still another object, therefore, is to provide an A-frame and mounting brackets which attach the blade to the vehicle and overcome the aforementioned difficulties.
Hitherto, conventional plow systems, which weigh from 500 to 800 pounds, have had approximately half of the mass of the plow system concentrated in the blade. The large weight poses great difficulty in connecting the system to the vehicle. Thus, most owners leave their plow systems connected to the vehicle between snow storms. Thus a large weight is held out in front of the vehicle during otherwise normal driving, which in turn creates a large moment of inertia acting upon the front end resulting in excessive and unnecessary wear on the vehicle and, in addition, causes vehicle handling difficulties thereby posing driver-safety problems. A further object, therefore, is to incorporate a blade connection mechanism into the plow system design in order to facilitate quick and easy connecting of the blade structure assembly to, and disconnecting it from, the plow system's A-frame assembly, in contrast with removing the entire plow system, off and away from the plow vehicle.
The foregoing and further objects are addressed hereinafter.
The above objects are attained, generally, in a plow to effect plowing action on a material at a surface, whereby the plow comprises: a blade having an arcuate-shell face region, and a bottom plate that interfaces with the material at the surface being plowed, where the bottom plate is secured to and extends along the lower edge of the arcuate-shell face region and is disposed at an angle .phi. to the portion of the face region of the blade to which it is secured. The bottom plate is also wide enough to place the upper portion thereof above rigid obstacles usually encountered during the course of plowing. The angle .phi. is the external angle formed between the face region of the plow blade and the bottom plate at the junction of the two structures and is an angle greater than 180.degree. and less than 360.degree.. The bottom plate is disposed at an angle .alpha. to the roadway. An A-frame assembly serves to attach the blade to a vehicle, and a blade connecting mechanism serves to attach the blade to the frame.